A050236 Indices of consecutive squares palindromic primes; x such that x^2 + (x+1)^2 is palindromic and prime.

1, 9, 12, 1262

Offset: 1

Author

Eric W. Weisstein

Keywords

• nonn
• nice
• hard
• base

Comments

No other terms < 20000000000. - Patrick De Geest, Aug 15 1999

Links

• Patrick De Geest, Palindromic Sums of Squares of Consecutive Integers
• Carlos Rivera, Puzzle 14. Pal-Primes and sum of powers, The Prime Puzzles & Problems Connection.
• Eric Weisstein's World of Mathematics, Palindromic Prime

Crossrefs

Cf. A050239.

Intersection of A027861 and A027571.

Programs

Mathematica

Flatten[Position[Total/@Partition[Range[1300]^2,2,1],?(PrimeQ[#] && IntegerDigits[#]==Reverse[IntegerDigits[#]]&)]] (* _Harvey P. Dale, Dec 09 2014 *)

PARI

isok(m) = my(p=m^2+(m+1)^2); if (isprime(p), my(d=digits(p)); (d == Vecrev(d))); \\ Michel Marcus, Jan 05 2019